Front and back of the secondary distribution box

A secondary distribution box typically features a front with access doors and circuit breakers, and a back designed for cable entry, busbar connections, and mounting, ensuring safety and organized power distribution.

Front of the Secondary Distribution Box

The front side of a secondary distribution box is designed for user access and operational control. Key features include:

• Inner and outer doors: These provide safety and aesthetic appeal, often with a powder-coated finish for durability and outdoor use .
• Circuit breakers: Large three-phase breakers are installed to control and protect the connected loads .
• Indicators and meters: Some boxes include metering systems to monitor voltage, current, and load conditions .
• Safety and accessibility: The front layout allows operators to safely switch circuits on or off without exposing live components .

Back of the Secondary Distribution Box

The back side is primarily for cable management and electrical connections:

• Cable entry and exit points: Bottom or rear entry points allow incoming and outgoing cables to connect to the box safely .
• Busbars and copper strips: Main connections are made using copper busbars, ensuring reliable contact and efficient current flow .
• Mounting provisions: The back is designed to secure the box to walls, poles, or other structures, maintaining stability and alignment .
• Protection against environmental factors: Rainproof tops and sealed back panels prevent water ingress and protect internal components .

Functional Overview

Secondary distribution boxes serve as sub-distribution points, typically supplying power to specific areas such as floors in a building or individual buildings in a complex. They form part of a three-level protection system:

• Primary distribution: Main distribution cabinet from the transformer.
• Secondary distribution: Sub-distribution box with three-phase breakers.
• Tertiary distribution: Switch boxes or final outlets for individual equipment . This design ensures organized power distribution, safety, and compliance with electrical standards, with the front providing operational access and the back handling connections and structural support.